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Appendix VI.                              1175

The Rateau turbine, Fig. 1032, is a multiple-stage
' de Laval' turbine. Steam enters at D, through throttle s
and nozzles to wheels c c. Between each pair of wheels divisions
B B are fixed in the casing A to carry guide blades B1 BX, shewn
in larger section; wheels and divisions completely filling the
turbine chamber. The forms of blade for wheel and casing are
both shewn in plan view, and the rivet fastening is also apparent.
The exhaUst escapes at G. The shaft,D enlarges in diameter by
steps, so that the wheels may be easily -driven upon it. The
governor is not shewn, but can be understood from p. 721. The
balls flying outward put one or other of the. bevel wheels in gear
on a separately driven shaft, and a screwed spindle is thereby
rotated in one direction or the other to act on the throttle valve E
by lever F. This turbine uses 18 Ibs. steam per B.H.P. hour, the
pressure falling from 120 to 1*63 Ibs. absolute.

The Riedler-Stumpf turbine has a single Pelton wheel
of most interesting construction. Referring to Fig. 1033, the
enlarged section shews a wheel A with two series of buckets in
parallel rows. Steam enters by nozzles F F, of which there are
a large number connected to the high-pressure chamber c round
the wheel circumference. The outlets "have square sections in
order to cover the buckets more efficiently, and the steam is
rejected by the first set of buckets GG into the fixed guide
channel H. Trie latter returns it. to the wheel, where, after
passing through the secondary buckets j j/ it flows into the
exhaust chamber; at a low absolute velocity. Also, the buckets j
have a more abrupt angle than those at o,, because meanwhile the
relative velocity of the stream has' been decreased, and its
direction changed. The exhaust chamber D is directly connected
to surface condensers E E, and the wheel A is overhung on the
bearing B. A consumption of 14 Ibs, steam per B.H.P. has been
obtained with the wheel as shewn, as against 40 Ibs, when driving
one set of buckets only,                                                             \

The Curtis torbinti Fig. 1033, has a vertical shaft # driven
by two wheels a and b, connected usually to .a dynajoio h> the
whole being supported on a sf>@dally-de$ipiecj footstep /. An
enlarged section of wheel Z> shews three sets of blades m mt while